As the internet grows, controlling access to undesirable websites and content is a pressing issue. For example parents may wish to prevent their children from accessing websites with graphic depictions of crime, violence, pornography or other adult content. Likewise, many companies may wish to limit access of their employees to content which they deem undesirable during work hours, including not only the above, but also, for example, social networking sites and sports sites which may be perceived to be unproductive use of employee time. This issue applies not only to websites, but also to other forms of content available over the Internet such as download services, file sharing, mobile apps etc.
Typically, access to content is filtered by an application installed on each client device (laptop, desktop computer, mobile, tablet etc). Another approach is to carry out the filtering at the customer side gateway (e.g. the gateway connecting the local area network to the Internet). With both these approaches, a user attempting to access undesirable content will be denied access by the content filter. However, these methods lack flexibility and may have difficulty keeping up with the proliferation of mobile and wireless devices.